Generally, a photovoltaic system includes a photovoltaic array, an inverter and a load (and/or a power grid). The photovoltaic array includes one or more photovoltaic modules connected in series-parallel, and converts received light energy into direct-current electrical energy for output. The direct-current electrical energy outputted by the photovoltaic array is converted into alternating-current electrical energy by the inverter, to supply power to the load or be fed into the power grid.
In some cases such as snow melting and deicing, the photovoltaic system needs to absorb electrical energy from the power grid to heat the photovoltaic module. However, due to different parameters of the photovoltaic modules and the non-uniformity of the snow and ice, power consumed by the photovoltaic modules are different under a fixed total power, and thus some modules may receive excessive reverse power which causes performance degradation or damage.